Pulse Prediction

The Back Story

For IEEE Fellow Monte Ross, the dedication last spring of a new telescope in Harvard, Mass., is a kind of vindication. The facility, designed and operated by Harvard University’s Paul Horowitz, is the first to be specially crafted to search for signals of light, rather than radio, from intelligent extraterrestrial beings [see Ross’s article, ”The New Search for E.T. ,” in this issue].

Although Ross has no personal stake in the new instrument, for more than four decades he has championed the idea of searching the cosmos for pulsed optical signals. ”With the advent of the laser [in 1960], I realized that it made a lot of sense for use in communication,” he told IEEE Spectrum.

Ross has devoted his professional life to using lasers in communications. After graduating from the University of Illinois at Urbana-Champaign with a B.S. in electrical engineering and from Northwestern University with an MSEE, he did research in optical communications and invented the diode-pumped Nd:YAG (neodymium-doped yttrium-aluminum-garnet) laser. At McDonnell Douglas (now part of Boeing), he oversaw a 400-person division that developed, among other things, the first space-laser communications system.

Just as laser pulses now carry most of the long-distance traffic on this planet, they would also be ideal for intragalactic communication, Ross has long argued. In a letter published in Proceedings of the IEEE in November 1965, he first suggested that other intelligent civilizations might use pulsed lasers to contact us.

”It took a while for other people to finally join the parade,” Ross says. But as one radio SETI project after another has failed to detect any indisputable sign of life, the logic of Ross’s idea has started to take hold. He admits that the chances of detecting anything at all are still slim, despite the new telescope and other, grander projects in the works. Even so, he’s hopeful.

”We have no evidence that aliens are trying to contact us, except the logic of the physics of the thing,” he says. ”But you have to be optimistic to do anything in this field.”